Subject: RE: Delivering MPLS Services over L3VPN

From: "DECRAENE Bruno RD-CORE-ISS" <[email-masked]>
Date: Mon, 3 Jul 2006 10:29:22 +0200

Ron,

That seems indeed a good idea.

Would you also consider an option where addresses of the VPN sites
(addresses of C0, C3...) would be distributed directly between CE though
iBGP sessions, without passing through PE?

I would see two advantages:
- This reduces the number of VPN routes on the PE, as this becomes a
significant scaling consideration in VPN networks. Both in the MP-BGP
control plane (on PE and RR) and in the PE forwarding plane (FIB
memory).
- The C-next-hop attribute is no more necessary.
(-it also reduces the number of MP-BGP updates since "Link-bandwidth"
updates are not anymore carried by the SP)

It does have disadvantages as:
- It requires additional iBGP sessions on the CE
- It requires a full mesh of iBGP sessions between CE (or the use of RR
by the customer). However the use of an iBGP full mesh as its advantage
as it increase route diversity which is useful for TE. (C3 could be
reached by CE2 and CE3 and it would be better if CE1 has the choice).

However, regarding the need for iBGP full mesh:
- The number of iBGP sessions would probably be significantly smaller
than the number of RSVP-TE sessions so it does no add that much load on
the CE
- The configuration burden (when adding a new VPN site) could be
addressed though auto-discovery (For example by adding a newly defined
BGP extended community ("BGP RR group A") attached to CE loopback
addresses advertised in BGP)

Would you consider both options in the draft?

Thanks,
Best regards,
Bruno

> -----Original Message-----
> From: Ron Bonica [mailto:[email-masked]]
> Sent: Monday, June 12, 2006 8:06 PM
> To: [email-masked]
> Subject: Delivering MPLS Services over L3VPN
> 
> Folks,
> 
> Please review a draft at the following URL:
> 
> http://www.ietf.org/internet-drafts/draft-bonica-mplsvpn-00.txt
> 
>                                   /as individual contributor
>                                   Ron
> 
> 
> 
> Abstract
> 
>    This document describes procedures that can be used to deliver MPLS
>    services over Layer 3 Virtual Private Networks (L3VPN).  Using
these
>    procedures, a VPN customer can signal MPLS Label Switched Paths
(LSP)
>    from Customer Edge (CE) router to CE router.  Although a Service
>    Provider (SP) network carries the Customer LSP (C-LSP) from one CE
>    router to another, the C-LSP does not interact with the SP
network's
>    routing or signaling infrastructure.